I have created a function app for iot hub ingest telemetry data to azure digital twin using visual studio 2022 and the function is successfully being published but the data is fail to deliver. The following is my function app code: The figure below is from the application insights of my function app : (im new to azure so i have little idea how to solve these issue)

Hello @TEE WEI KIAT, welcome to this moderated Azure community forum. The error message tells is the CloudEvent cannot be converted. It seems a string is ingested? Please try to find out what type of parameter contains the incoming message first. Because you use a EventGridTrigger, my first thoughts are about 'EventGridEvent'. Check out my blog post on using Azure Digital Twins. It contains a GitHub example based the IoT Hub EventGrid output. There the message is ingested as a 'EventGridEvent'. For an EventHub, you typically use the EventData class . But perhaps you just need to stick to 'string' first. Let us know if this helps. If the response helped, do "Accept Answer". If it doesn't work, please let us know the progress. All community members with similar issues will benefit by doing so. Your contribution is highly appreciated.

IoTHub ingest function to azure digital twin (failed)

Accepted answer

Sander van de Velde | MVP 33,951 Reputation points MVP

2024-04-03T06:26:03.6033333+00:00

Hello @TEE WEI KIAT,

welcome to this moderated Azure community forum.

The error message tells is the CloudEvent cannot be converted.

It seems a string is ingested?

Please try to find out what type of parameter contains the incoming message first.

Because you use a EventGridTrigger, my first thoughts are about 'EventGridEvent'.

Check out my blog post on using Azure Digital Twins. It contains a GitHub example based the IoT Hub EventGrid output. There the message is ingested as a 'EventGridEvent'.

For an EventHub, you typically use the EventData class.

But perhaps you just need to stick to 'string' first.

Let us know if this helps.

If the response helped, do "Accept Answer". If it doesn't work, please let us know the progress. All community members with similar issues will benefit by doing so. Your contribution is highly appreciated.
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TEE WEI KIAT 40 Reputation points

2024-04-03T14:42:24.54+00:00

Hi @Sander van de Velde | MVP , i have did some modification to my code as follows:

Now im thinking of maybe there is error while getting the decoded data(btw im ingesting sensor readings and device status from a ESP8266 module in the form of strings) (the schema of my dtdl model is temp,humd,soil are double where the rest are in string).

The following is the logger of my functions :

Thank you in advance.

Sander van de Velde | MVP 33,951 Reputation points MVP

2024-04-03T16:33:34.95+00:00

Hello @TEE WEI KIAT,

looking at the response, the body property 'eyJ...' seems to be encoded as Bas64.

It also seems you decoded it properly because there is a temperature, humidity etc. shown.

regarding the Error message, this is just code. Just check which field is giving a problem.

If needed convert strings into doubles. This is something you have to do yourself.

Finally, give all twin properties in the Azure Digital Twins environment a value.

This is because the update does not like 'null' values.

Good luck.

TEE WEI KIAT 40 Reputation points

2024-04-03T17:30:13.12+00:00

Hello @Sander van de Velde | MVP ,
After specified the format for updateTwindata.AppendData(), the problem has been resolved. Thank you for your support.

Sander van de Velde | MVP 33,951 Reputation points MVP

2024-04-03T18:04:01.7433333+00:00

Hello @TEE WEI KIAT,

You're welcome.

I wish you a great time working on Azure Digital Twins.
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